JP2007086779A - Fiber coating processing and slitting for non-confined light leakage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber in which absorption of a portion of light by coating or the like is reduced. <P>SOLUTION: An optical fiber and methods of processing and manufacturing an optical fiber comprising a core, a cladding and a coating covering a segment of the cladding proximate to an end of the optical fiber are presented where patterned apertures are provided in the coating such that a portion of light propagating in the cladding escapes through the patterned apertures of the coating. The patterned apertures allow non-confined light to escape from the cladding in the coating region to provide reduced absorption of the non-confined light by the coating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to optical fibers and, more particularly, to a method for removing excess power from a coated fiber end and openings patterned in the coated fiber end.

  Typically, the optical fiber is attached at at least two locations inside the optical package. In general, the optical fiber is mounted in front of an optical device that emits light, such as a diode laser. In addition, the optical fiber is held at a feed-through point of the optical package so as to seal the package and prevent leakage from the package into the atmosphere and inflow from the atmosphere into the package. In some cases. The end of the optical fiber inside the optical package may be metallized for the purpose of mounting and sealing the optical package. The end portion of the optical fiber is soldered at a predetermined position so as to be accurately aligned with the diode laser and held at that position for a long time.

  If the optical package changes, the attachment point of the optical fiber changes according to the change. Typically, a significant portion of the optical fiber end is metallized during the manufacturing process. This allows the same type of optical fiber to be used in various optical packages and / or light sources from a manufacturing standpoint. This is because the optical fiber may be soldered at any position of the metallized portion in accordance with the optical package. An object of the present invention is to provide an optical fiber that can reduce the light absorbed by such a coating.

  The present invention is implemented as an optical fiber having a core having a first refractive index and a clad having a refractive index smaller than the first refractive index of the core and surrounding the core. The coating is formed so as to form an opening pattern in a part near the end of the optical fiber, and to release a part of the light propagating through the cladding from the opening pattern of the coating. The aperture pattern can reduce the absorption of a portion of the light by the coating.

  In addition, the present invention is implemented as an optical fiber that receives light from a light source. The optical fiber has an optical fiber core having a first refractive index for receiving light from the light source, a refractive index smaller than the first refractive index of the optical fiber core, And a surrounding cladding. The optical fiber further has a coating that covers the cladding in the vicinity of the end of the optical fiber and has an opening pattern. The end of the optical fiber has an edge proximate to the light source, and the aperture pattern reduces the absorption of a portion of light within the coating as a portion of the light escapes from the coating.

  The present invention includes a core having a certain refractive index, a clad having a refractive index smaller than that of the core and surrounding the core, and a coating applied to a part of the surface of the clad. It is implemented as a method of processing an optical fiber that is partially located near the end of the optical fiber. The method selectively removes a portion of the coating to form an opening pattern in the coating.

  The present invention is also implemented as a method for manufacturing an optical fiber. The method includes the steps of providing a core having a certain refractive index and forming a clad having a refractive index smaller than that of the core and surrounding the core. The method further includes forming a coating having an opening pattern on a surface of a portion of the cladding near the end of the optical fiber.

  The invention can be best understood by reading the following description in conjunction with the accompanying drawings. Note that by convention, the scales described in the accompanying drawings are not scaled. Also, the dimensions of the various forms have been expanded or reduced for the sake of clarity of the drawings.

  Reference is now made to the drawings, wherein like reference numerals are used to refer to like elements throughout the drawings that make up the drawing. 1A, 1B, 1C, and 1D illustrate optical fiber ends that have been metallized, which is a prior art example. The optical fiber 102 has an end 104, which is typically provided with a metal that can be placed inside an optical package (not shown), eg, aligned with a diode laser (not shown). It has a rendering unit 108.

  FIG. 1A shows an optical fiber 102 that is well known to those skilled in the art. Here, the metallization part 108 is arranged at the end part 104 up to the lens-like end part 106. The lenticular end 106 is lenticularly finished to focus the optical power from the diode laser, as will be described below. The optical fiber 102 may include a fiber buffer unit 110 between the fiber end 104 and the remaining part of the other optical fiber 102.

  FIG. 1B illustrates another known optical fiber end 104 '. In this example, a planar end 112 well known to those skilled in the art is used, and the metallization 108 is applied to the planar end 112 over the entire length of the optical fiber 104 '.

  1C and 1D show two optical fiber ends 104 "and 104" ", respectively, well known to those skilled in the art. In these examples, the metallization portion 108 does not extend the entire length of the optical fiber ends 104 "" and 104 "". 1C and 1D are diagrams showing examples in which the bare clad 114 is exposed in different portions. In these examples, the end is illustrated as a lenticular end 106.

  The optical fiber may be provided with metallization portions 108 at least at two locations inside the optical package (not shown) for all types of optical fiber ends. The first location is where the fiber end is attached in alignment with a diode laser (not shown). The second location may be a penetration point of the optical package for the purpose of sealing the optical package (not shown).

  In general, the end of the optical fiber is even more effective if the entire metallization is applied, such as the ends 104 and 104 'shown in FIGS. 1A and 1B. In the case of partial metallization where bare cladding 114 is exposed as shown in FIGS. 1C and 1D, additional processing steps may be required. This processing step may vary depending on the optical package, light source, and application, and may not be very effective for manufacturing purposes.

  1A, 1B, 1C, and 1D illustrate an optical fiber with a metal coating. However, it should be understood that the present invention can be practiced on optical fibers that are damaged by absorbing light that is coated with the optical fiber and the coating is not confined. For example, acrylate, polyimide, or carbon can be used for the coating.

  FIG. 1A illustrates the lenticular end 106 and the fiber buffer portion 110, and FIG. 1B illustrates the planar end 112. However, as a matter of course, the end portion of the optical fiber may be other end portions including a lens shape and a planar shape. The type and shape of the end may be determined according to the requirements determined by the light source and the application. The requirements defined by the light source include the type of light source, eg, a diode laser, the light power of the light source, and the optical brightness (optical brightness). This optical brightness may further depend on the numerical aperture of the optical fiber. The fiber buffer unit can be used in any optical fiber.

  A diode laser is a typical light source. Typically, in a diode laser, there is light that is confined and light that is not confined. For example, a diode laser may have fast axis power and slow axis power. In general, fast axis power and slow axis power correspond to confined light and unconfined light, respectively. By finishing the end of the optical fiber into a lens shape, it is possible to improve the coupling property from the fast axis power diode laser to the multimode optical fiber. However, even when finished in a lens shape, it is difficult to confine all of the fast axis power in the core of the optical fiber. Furthermore, the slow axis power is typically not confined to the core and spreads to the cladding.

  Next, with reference to FIGS. 2A and 2B, examples of coupling between a diode laser and a conventional multimode optical fiber, respectively, for fast axis power and slow axis power will be described. A core 202 and cladding 204 of a multimode optical fiber are illustrated in FIGS. 2A and 2B. In this example diagram, the fast axis power and the slow axis power are shown. Of course, this relationship also applies to light that is not confined.

  FIG. 2A is a diagram illustrating the relationship between the core 202 and the clad 204 for the fast axis power 208 emitted from the diode laser. Here, it is assumed that the optical fiber is properly aligned with the diode laser. Line 206 represents the receiving cone of the fiber. In general, the fast axis power has a Gaussian shape. With respect to the fast axis, it is desirable that most of its power 208 be inside the core 202. Only a small part with low power leaks into the cladding. Therefore, in general, the fast axis power is not so large as to propagate through the cladding.

  FIG. 2B is a diagram illustrating the relationship between the core 202 and the clad 204 for the slow axis power 210 emitted from the diode laser. Again, assume that the fiber is properly aligned with the diode laser. Line 206 represents the receiving cone of the fiber. For multimode diode lasers, the slow axis is generally indicated by the sum of a number of single mode Gaussian power curves. Therefore, in general, the slow axis power is expressed as a curve 210. With respect to slow axis power, typically, most of the power 210 resides inside the core 202 and further extends to the outside of the receiving cone 206, to the cladding 204. The slow axis power 210 extending to the cladding 204 may have a high power. Therefore, the slow axis power 210 may be connected to the clad 204 without being confined in the core 202, and may further propagate through the clad 204.

  Light that is not confined may propagate through the cladding 204 as a cladding mode or leak out of the cladding. However, the cladding at the fiber end is coated (not shown in FIGS. 2A and 2B) and unconfined light exiting through the coating is absorbed by the cladding-coating interface, May cause local heating. Furthermore, if unconfined light propagates in the long axis direction of the optical fiber, it may be absorbed by the buffer region beyond the end of the coated optical fiber.

  In general, the confined light is light that is reflected or refracted within the core of the fiber. Unconfined light is either absorbed at the cladding-coating interface or leaks through the coating. Desirably, the absorption of unconfined light at the cladding-coating interface is suppressed.

  Next, with reference to FIG. 3A, FIG. 3B, and FIG. 3C, the damage by absorption of the light which is not confined in the optical fiber end part with which the conventional optical fiber was coated is demonstrated. The inventor of the present application has found that when the power of a diode laser is increased or when the brightness is high, absorbed non-confined light has an adverse effect, and the conventional optical fiber coating is I discovered that it could be damaged. FIG. 3A illustrates damage 302 in the region of the fiber buffer section 110. FIG. 3B illustrates a conventional optical fiber end 104 ″ with the coating 108 removed to expose the bare cladding 114. In this example, absorption damage 304 is seen in the end region of the coating 108 at the end 104 ″. Absorption of unconfined light creates hot spots that can result in damage in any region of the fiber end. This is illustrated in FIG. 3C as damage 306 to the coating.

  Although a single point of damage is illustrated in this figure, damage may occur in multiple regions both in the region of the fiber end 104 and the fiber buffer portion 110. This figure illustrates the lenticular end 106. However, of course, damage to the fiber coating can occur if there is optical power that is not confined to the core of the multimode optical fiber, even in other types and shapes of fiber ends and coated fibers. is there.

  The example optical fiber may have a 105 micrometer core and a 125 micrometer cladding. Also, the present optical fiber example may have an NA of 0.15 to 0.22. The inventor has shown that local hot spots may be formed when the power of a continuous wave (CW) diode laser greater than 1 watt is incident on a multimode optical fiber of NA 0.15. discovered. Also, high optical power above about 4 watts from a single radiator can damage the optical fiber coating.

  In addition to high optical power, damage can occur depending on optical brightness. For example, in an optical fiber having a small NA, a problem of hot spot formation accompanying an increase in brightness may occur more frequently in comparison with an optical fiber having a large NA. In addition, this can lead to damage to the fiber, coating, or epoxy resin (buffer material near the end of the optical fiber) due to laser power absorption. Furthermore, there is a possibility that a catastrophic defect may be caused to the optical package in the end. Such damage may initially manifest as a discoloration of the coated material of the fiber or buffer material such as acrylates. In addition, the damage can cause fiber breakage or deflection that can rapidly degrade the optical fiber and further reduce output power and cause failure of the entire optical package.

  There is also a relationship between optical power and NA (brightness). As the drive current of the light source increases and the optical power increases, both the confined optical power and the unconfined optical power change. In the case of a small NA, the optical power that is not confined from earlier than when the NA is large begins to leak out of the receiving cone (core NA) of the fiber 206 and becomes connected to the cladding. Thus, hot spots and fiber damage can occur at lower optical powers with smaller NAs than with larger NAs.

  In a typical optical package, the coated optical fiber is typically soldered at two attachment points. These points may be a few millimeters apart. At the solder attachment point, the solder may be connected to the base (base) of the optical package. Heat generated by unconfined light absorbed and present in the cladding may escape through this solder connected to the base. Typically, the coating is very thin between the solder attachment points. The coating may not be able to dissipate the accumulated heat and thus fiber damage may occur between the solder connection points. Of course, the coated optical fiber can be attached to the optical package at one attachment point or more than one attachment point.

  Next, an embodiment of the present invention will be described with reference to FIGS. 4A to 4E. It is desirable to apply a coating with patterned openings at the ends of the optical fiber 402 to reduce damage to the optical fiber. In the exemplary embodiment of the present invention, openings arranged in a pattern are provided in the coated part, so that unconfined light that has been absorbed in the past has been removed from the openings in the coated part. It is desirable to be able to escape. It is desirable to reduce the absorption of unconfined light, so that optical fiber hot spots and resulting damage are avoided.

  FIG. 4A is a diagram showing an example embodiment according to the present invention. In this example, a coating 408 having an opening pattern is disposed along the length of the optical fiber end 404 of the optical fiber 402. The coating 408 having an opening pattern according to this example embodiment is preferably formed by removing the coating spirally along the length of the fiber end 404.

  As a matter of course, in the embodiment of the present invention, the coating may be removed in the form of a plurality of grooves (grooves) inclined with respect to the length of the optical fiber 402. As a matter of course, each groove portion may or may not extend so as to completely surround the periphery of the fiber end portion 404. For example, the optical fiber end 404 may be placed in an optical package (not shown) and then the coating may be removed using a laser. The coating below the optical fiber end 404 may not be removable with a laser. This is because the laser may be able to melt and remove the coating through the optical fiber for the coating below the optical fiber. Thus, the groove of the coating 408 having an opening pattern may or may not continue to the bottom of the optical fiber end 404.

  In this embodiment, a lenticular end 406 and a fiber buffer 410 are shown. Of course, a coating 408 having an aperture pattern may be used for any type of multimode fiber where fiber damage may be caused by absorption of unconfined light. It is also possible to use a coating 408 having an opening pattern for a portion of the fiber end 404. The optical fiber 402 may be a lens-shaped end 406, a planar end 414 as shown in FIG. 4B, or an end type determined by at least a light source, optical fiber, optical package, application, or any combination thereof. Can be provided. Further, the optical fiber 402 may not include the fiber buffer unit 410 as shown in FIGS. 4B and 4C.

  FIG. 4B shows an example of a second embodiment according to the present invention. In this example, a coating having an opening pattern is disposed along the length of the optical fiber end 404 ′ of the optical fiber 402. The coating 408 having an opening pattern according to the present embodiment is realized by removing a plurality of circumferential groove-like coatings that exist along the length of the fiber end 404. In the second embodiment, the coating 412 having the pattern is formed in a groove portion perpendicular to the longitudinal direction of the optical fiber 402.

  Of course, each groove need not completely surround the circumference of the fiber end 404 '. As described above, the coating may be removed after optical fiber end 404 'is placed in an optical package (not shown). Thus, the groove on the coating 412 having the opening pattern may or may not be continuous at the bottom of the optical fiber end 404 '.

  In this second embodiment, a planar end 414 is shown. Of course, the coating 412 having an aperture pattern can be used for any type of multimode fiber where the fiber can be damaged by unconfined optical power. A coating 412 having an opening pattern may be applied only to a portion of the fiber end 404 '. In the second embodiment, a fiber buffer unit 410 may be further provided. Depending on at least the light source, the optical fiber, the optical package, the application, or any combination thereof, the second embodiment may be implemented with a different type of tip, such as the lenticular end 406.

  FIG. 4C shows an example of a third embodiment according to the present invention. In this example, a coating 416 having an opening pattern is disposed along a portion of the optical fiber end 404 ″ of the optical fiber 402. The coating 416 having an opening pattern according to the third example embodiment is realized by removing the coating at a plurality of polygonal or oval (oval) openings along a portion of the fiber end 404 ''. ing.

  An example of a plurality of openings in the coating 416 having an opening pattern is a circular opening arranged at regular intervals. Of course, the openings may have various polygonal shapes, and may even be arranged at irregular intervals.

  FIG. 4D is a cross-sectional view of a third embodiment according to the present invention. A coating 416 having an opening pattern of the optical fiber 402 surrounds the cladding 418. An opening 420 is provided in the coating 412 to expose the cladding 418. The openings 420 are shown as oval shapes arranged at irregular intervals. However, the openings 420 may have any shape and may be arranged at regular intervals.

  Of course, the opening provided in the coating need not extend around the entire circumference of the fiber end 404 ″. As described above, the removal of the coating may be performed after placing the optical fiber end 404 ″ in an optical package (not shown). Therefore, the opening may or may not be provided at the bottom of the optical fiber end 404 ″.

  In the third example embodiment illustrated in FIG. 3C, a portion 418 of the optical fiber end 404 ″ is a bare cladding. Of course, the coating may be stretched along the length of the optical fiber end 404 ″. It will also be appreciated that the coating 416 having an aperture pattern can be applied to any type of multimode fiber where fiber damage can occur due to unconfined optical power. In the third embodiment, a fiber buffer unit 410 may be further provided. Although the third embodiment is illustrated in the form with a lens-shaped end 406, the present invention is suitable for at least a light source, an optical fiber, an optical, and the like, with the planar end 414 and other types of tips. You may implement it according to a package, an application use, or any combination thereof.

  FIG. 4E shows a fourth embodiment according to the present invention. The example includes coatings 416 and 422 having an opening pattern along a plurality of optical fiber ends 404 ″ ″ of the optical fiber 402. The coating 416 having the opening pattern is as described above. The coating 422 having an opening pattern according to the fourth embodiment is different from the example in which the coating is removed at a part of the fiber end portion 404 ′ ″ and a plurality of polygonal openings are formed in a regular shape. It is an example.

  As an example of the plurality of openings of the coating 422 having an opening pattern, a square-shaped opening arranged in a checkerboard pattern (checkered pattern) and arranged at regular intervals may be mentioned. Of course, the opening may have various polygonal shapes. In the fourth embodiment, the pattern of the two types of polygonal openings is shown. However, as a matter of course, in the present invention, the grooves as shown in FIGS. 4A and 4B, and FIGS. 4C and 4E are used. The polygons shown may be combined.

  In FIG. 4E, a region of the coating having two opening patterns and a region of two bare claddings 418 are shown, but it should be understood that the number of coating regions having an opening pattern and the number of naked claddings The number of regions can be any number, as long as the coating is applied where the optical fiber end 404 '' 'is attached to the optical package, as described above. Of course, regions coated with a plurality of types of opening patterns may be combined without being separated by the bare cladding 418.

  Of course, the polygonal opening configured in the coating may not be present all around the fiber end 404 ″ ″. As described above, the coating may be removed after optical fiber end 404 "" is placed in an optical package (not shown). Therefore, a polygonal opening may or may not be formed at the bottom of the optical fiber end 404 ″ ″.

  In the fourth embodiment shown in FIG. 4E, the portions of the optical fiber end 404 "" are bare clad. Of course, a coating may be applied over the entire length of the optical fiber end 404 "". Of course, the patterned coating 416 can also be applied to any type of multimode fiber where fiber damage can occur due to unconfined optical power. The fourth embodiment may include a fiber buffer unit 410. Although the fourth embodiment is illustrated with a lenticular end 406, the present invention applies at least a light source, optical fiber, optical package, and application to various types of tips, including a planar end 414. It can be determined as appropriate depending on the application or any combination thereof.

  Although the first to fourth embodiments do not illustrate a coating that covers the fiber end 406 or 414, it will be appreciated that the coating may extend to the tip of the fiber.

  FIGS. 4A to 4E show only a plurality of shapes by way of example, and it is possible to escape (leak) absorbed unconfined light by removing the coating in various shapes.

  Pattern shape type and pattern placement on the fiber end depends at least on the type of application, fiber core NA, light source power, and optical package, and mounting points within the optical package And decide. Thus, even in situations where higher power or brightness appropriate for a particular application is used, the present invention is designed to reduce fiber damage by flexibly interpreting example embodiments of the present invention. What is necessary is just to use for attachment with respect to the optical package of fiber.

  Referring now to FIG. 5, an example fiber optic post-processing method for implementing an example fiber optic end according to the present invention is shown. In step 500, a fiber end with a conventionally known coating is placed in an optical package that includes at least one of a light source and an optical package. In step 502, the coated fiber end is soldered after accurately aligning the light source and the fiber end at least where the coating is applied over the optical fiber.

  According to an embodiment of the present invention, in step 504, the pattern shape based on the opening is removed from the attached optical fiber. The portion of the coating is removed by the laser, and the bare cladding is exposed in the form of the above opening pattern example. In step 506, the coated optical fiber having the opening pattern according to the embodiment of the present invention is completed. Also good. Alternatively, a portion of the coating may be removed using chemical or mechanical means.

  The use of the above-described example of the optical fiber post-processing method is advantageous in using an optical fiber that is conventionally known in the art. To meet the requirements of at least one specific application, optical package, and light source without selecting an optical fiber with expert knowledge, using a fiber with a coating that is well known in the industry. It is possible to attach to. After attaching the optical fiber, a portion of the coating may be removed, at least depending on the particular light source and application. Therefore, it is not necessary to use a special fiber according to at least the optical package and the light source. Also, an optical fiber with a coating having an aperture pattern reduces the risk of absorbed unconfined optical power forming hot spots and damaging the optical fiber. Therefore, the lifetime of the optical fiber and the device attached to the optical fiber can be extended.

  Although not shown, naturally, using the embodiment of the present invention, after coating the optical fiber, a coating having an opening pattern may be formed in the manufacturing process of the optical fiber. Thus, in the optical fiber manufacturing process, a core is prepared and a cladding is formed around the core. A coating may be applied to at least a part of the clad at the end of the optical fiber. Then, a part of the coating may be removed using a laser as in the embodiment according to the present invention. Therefore, after the coating is applied, a coating having an opening pattern can be formed in the optical fiber manufacturing process. It is also possible to remove a portion of the coating using chemical or mechanical means.

  With reference to FIG. 6, an example of a method for manufacturing an example of an optical fiber according to the present invention will be described. In step 600, an optical fiber core having a refractive index is provided in a manner well known in the art. In step 602, a cladding is formed around the core in a manner well known in the art. The clad may have a refractive index smaller than that of the core.

  In step 604, a mask with an aperture pattern is applied at least around the cladding over the fiber end. A mask with a pattern formed may be wound around the cladding. In this way, a mask having an opening pattern formed thereon may be prepared according to the embodiment of the present invention.

  In step 606, a coating is applied to at least a portion of the cladding at the end of the optical fiber, as described above, thus providing a coated end of the coated optical fiber. In step 608, the mask is lifted, and the mask having the aperture pattern applied in step 604 is removed from the fiber end portion, so that the coated fiber having the aperture pattern of step 610 is applied. Can be obtained. Here, the cladding is exposed in the opening pattern disposed in the coating.

  Next, with reference to FIG. 7, an alternative method of manufacturing an optical fiber according to the present invention will be described. In step 700, an optical fiber core having a refractive index is provided. In step 702, a cladding is formed around the core. The clad may have a refractive index smaller than that of the core. In step 704, it is desirable to coat at least a portion of the cladding at the end of the optical fiber and to coat the end of the optical fiber as previously described.

  In step 706, a photoresist is applied to the coating. In step 708, partial exposure (exposure) is performed on the photoresist using the mask on which the opening pattern described in the embodiment of the present invention is formed. In step 710, the photoresist that has not been irradiated (exposed) is removed. In step 712, the exposed coating under the unirradiated photoresist that has been removed may be etched. In step 714, the irradiated photoresist is removed to expose the coating, resulting in a coated fiber having an aperture pattern as described in step 716.

  As described in the example of the manufacturing method, an optical fiber coated with an opening pattern has the following steps: a) a step of pre-masking the optical fiber cladding (pre-masking), and b) a mask having an opening pattern. By chemically treating the optical fiber with irradiating (exposure) via, or c) after applying the coating, removing the coating to obtain a coating having an aperture pattern. Alternatively, after attaching the optical fiber to the optical package, the fiber with a coating well known in the art may be post-processed in a manner that uses a laser to remove the coating to form a coating having an aperture pattern.

  Although the present invention has been illustrated and described with reference to specific embodiments, the invention is not limited to the details shown. Various modifications may be made within the scope and equivalents of the claims without departing from the scope of the invention.

(Prior Art) is a side view of an optical fiber end that is metallized with a lenticular end for connection to an optical package. (Prior Art) is a side view of a metallized optical fiber end with a planar end for connection to an optical package. (Prior Art) Side view of a partially metallized optical fiber end with a lenticular end for connection to an optical package. (Prior Art) Side view of a partially metallized optical fiber end with a second lenticular end for connection with an optical package. (Prior Art) A diagram showing the relationship between the power of the fast axis of a diode laser and the transfer of power to the end of a multimode optical fiber. (Prior Art) A diagram showing the relationship between the slow axis power of a diode laser and the power transfer to the end of the multimode optical fiber. FIG. 6 is a side view showing damage to a coated fiber buffer section by absorbed and unconfined light in a conventional coated multimode optical fiber. 1 is a side view showing damage to an end face of a coating by absorbed and unconfined light in a conventional coated multimode optical fiber. FIG. FIG. 3 is a side view showing damage to a coated portion due to absorbed and unconfined light in a conventional coated multimode optical fiber. 1 is a side view of a coated optical fiber end having a first exemplary aperture pattern in accordance with the present invention. FIG. FIG. 4 is a side view of a coated optical fiber end having a second exemplary aperture pattern in accordance with the present invention. FIG. 6 is a side view of a coated optical fiber end having a third exemplary aperture pattern in accordance with the present invention. FIG. 6 is a cross-sectional view of a coated optical fiber end having a third exemplary aperture pattern in accordance with the present invention. FIG. 6 is a side view of a coated optical fiber end having a fourth exemplary opening pattern according to the present invention. 6 is a flowchart illustrating an example post-processing method for a coated fiber to obtain a coated optical fiber having an aperture pattern according to the present invention. 2 is a flowchart illustrating an example of a method of manufacturing an optical fiber with a coating having an opening pattern according to the present invention. 6 is a flowchart illustrating an alternative method of manufacturing a coated optical fiber having an aperture pattern in accordance with the present invention.

Explanation of symbols

102 optical fiber 104 fiber end 106 lenticular end 108 metallization 110 fiber buffer part 112 planar end 302 damage 304 damage 306 damage 402 optical fiber 404 fiber end 406 lensed end 408 coating 410 with aperture pattern Fiber buffer portion 412 Coating with opening pattern 414 Planar end 416 Coating with opening pattern 418 Cladding 420 Opening 422 Coating with opening pattern

Claims (23)

An optical fiber,
A core having a first refractive index;
A clad having a refractive index smaller than the first refractive index of the core and surrounding the core;
A coating that covers the cladding in the vicinity of the end of the optical fiber and has an opening pattern that allows some of the light propagating through the cladding to escape;
An optical fiber in which absorption of part of the light of the coating is reduced by the opening pattern.   The optical fiber according to claim 1, wherein the opening pattern includes at least one circumferential groove formed in the coating. The optical fiber has a central axis along a longitudinal direction;
The optical fiber according to claim 2, wherein the at least one circumferential groove is configured to be inclined with respect to the central axis.   The optical fiber according to claim 3, wherein the at least one circumferential groove includes a plurality of grooves.   The optical fiber according to claim 3, wherein the at least one circumferential groove is a spiral groove.   The optical fiber according to claim 1, wherein the opening pattern has a polygonal shape.   The optical fiber according to claim 6, wherein the opening pattern is arranged to be symmetric with respect to light that is not confined by laser light transmitted through the optical fiber.   The optical fiber according to claim 7, wherein the opening pattern is arranged in an irregular pattern with respect to the light that is not confined in the laser light that is transmitted through the optical fiber. An optical fiber that receives light from a light source,
An optical fiber core having an end for receiving light from the light source and having a first refractive index;
A cladding having a refractive index smaller than the first refractive index of the optical fiber core and surrounding the optical fiber core;
Covering the cladding in the vicinity of the end of the optical fiber, and having a coating having an opening pattern
The aperture pattern allows the part of the light to escape through the coating, and the absorption of the part of the light that occurs in the coating is reduced.   The optical fiber according to claim 9, wherein the light source emits confined light and unconfined light.   The optical fiber of claim 10, wherein the aperture pattern allows the unconfined light to escape through the aperture pattern of the coating.   The optical fiber according to claim 10, wherein an end portion of the optical fiber is finished in a lens shape to collect the confined light. An optical fiber comprising a core having a refractive index, a clad having a refractive index smaller than that of the core and surrounding the core, and a coating applied to a part of the surface of the clad. A method of treating the optical fiber, wherein the portion is located near the end of the optical fiber,
Defining at least one location in the coating to form an opening pattern;
Selectively removing a portion of the coating to form an opening pattern in the coating at the defined at least one location.   Further, the step of selectively removing a portion of the coating selectively removes the portion of the coating at the defined at least one location using one of a laser, chemical means, and mechanical means. The method according to claim 13, further comprising performing a removing process. Furthermore, selectively removing a portion of the coating comprises:
Attaching a portion of a portion of the optical fiber near the end to an optical package;
14. The method of claim 13, comprising processing the coating with a laser to remove a portion of the coating at the defined at least one location.   14. The method of claim 13, wherein the step of treating the coating forms at least one circumferential groove as the opening pattern.   14. The method of claim 13, wherein treating the coating forms a polygonal opening pattern. A method of manufacturing an optical fiber, comprising:
Providing a core having a refractive index;
Forming a cladding having a refractive index smaller than the refractive index of the core and surrounding the core;
Forming a coating having an opening pattern on a surface of a portion of the cladding near an end of the optical fiber. Further, the step of forming a coating having the opening pattern comprises:
Forming a coating on at least a portion of the surface of the portion of the cladding;
Treating the coating to form an opening pattern in the coating and forming a coating having an opening pattern. Further, the step of forming a coating having the opening pattern comprises:
Forming a coating on at least a portion of the surface of the portion of the cladding;
Forming a photoresist on the coating;
Exposing a portion of the photoresist to form a non-exposed portion of the photoresist;
Removing unexposed portions of the photoresist to expose a portion of the coating;
Etching the exposed coating to form an opening pattern, forming a coating having an opening pattern;
Removing the exposed photoresist to expose the coating. Furthermore, the step of forming the opening pattern includes:
Forming a mask having an opening pattern formed on the surface of the part of the cladding;
Forming a coating on the surface of the masked portion of the cladding;
The method of claim 18, comprising removing the mask on the cladding to form an opening pattern in the coating and forming a coating having an opening pattern.   The method of claim 18, wherein forming the coating having the opening pattern forms an opening pattern including at least one circumferential groove.   The method of claim 18, wherein the step of forming a coating having an opening pattern forms an opening pattern having a polygonal shape.

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